1. Field of the Invention
The field of this invention is nuclear reactors which use a coolant fluid under pressure, such as light water (H.sub.2 O).
2. Description of the Prior Art
U.S. Pat. No. 3,462,345 to Felix S. Jabsen discloses a nuclear reactor in which several fuel elements and individual control rods are provided in the reactor vessel. The individual control rods are longitudinally adjustable in the region of the fuel elements and are movable hydraulically in the guide tubes of the fuel elements, using the reactor coolant and a pump arranges outside the reactor vessel. For the purpose of moving the control rods hydraulically in the guide tubes, the pump generates suction or low pressure in a space provided at the cover of the reactor vessel by means of a suction line which leads from the lid of the reactor vessel to the pump. The pressure line is also connected to the lower part of the reactor vessel. The problem with this arrangement disclosed in the U.S. Pat. No. 3,462,345 is that if a break occurs in a suction line, this would cause a withdrawal of the control rods from the guide tubes, thereby jeopardizing the safety of the nuclear reactor.